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Neuropsychology Review Jun 2024Most people with dementia experience neuropsychiatric symptoms (NPS), including anxiety, depression or disinhibition. There is growing interest in the relationship... (Meta-Analysis)
Meta-Analysis Review
Most people with dementia experience neuropsychiatric symptoms (NPS), including anxiety, depression or disinhibition. There is growing interest in the relationship between NPS and cognitive impairment, but data is still limited. This study aimed to investigate the specific associations between NPS and cognition in people with dementia. MEDLINE, EMBASE and PsycINFO were searched for published, peer-reviewed studies of associations between at least one NPS and one cognitive ability in people with dementia. The quality of the studies was assessed with the NIH National Heart, Lung and Blood Institute's quality assessment tools. A meta-analysis was conducted using Robumeta package for R. Ninety studies were included. We found significant associations between NPS, global cognition and cognitive domains, e.g. apathy was associated with global cognitive and memory impairment; dysphoria was associated with worse attention; delusions with executive dysfunction. Increased NPS in people with dementia are associated with worse cognitive performance. There were few studies looking at associations between some neuropsychiatric clusters and cognitive abilities, and there was little research on causal relationships. Our review was limited by the inclusion of studies that reported associations in specific formats, and most included people with a diagnosis of Alzheimer's disease (AD). However, given the large number of studies, this is unlikely to have biased results. More research is needed that includes diverse people with different dementia syndromes. Registration: PROSPERO 2020 CRD42020165565.
Topics: Humans; Dementia; Cognitive Dysfunction; Cognition; Alzheimer Disease
PubMed: 37477839
DOI: 10.1007/s11065-023-09608-0 -
The International Journal of... Feb 2017Purpose/Aim: Approximately 44 million people worldwide have Alzheimer's disease (AD). Numerous claims have been made regarding the influence of diet on AD development.... (Review)
Review
UNLABELLED
Purpose/Aim: Approximately 44 million people worldwide have Alzheimer's disease (AD). Numerous claims have been made regarding the influence of diet on AD development. The aims of this systematic review were to summarize the evidence considering diet as a protective or risk factor for AD, identify methodological challenges and limitations, and provide future research directions.
METHODS
Medline, PsycINFO and PsycARTICLES were searched for articles that examined the relationship between diet and AD.
RESULTS
On the basis of the inclusion and exclusion criteria, 64 studies were included, generating a total of 141 dietary patterns or "models". All studies were published between 1997 and 2015, with a total of 132 491 participants. Twelve studies examined the relationship between a Mediterranean (MeDi) diet and AD development, 10 of which revealed a significant association. Findings were inconsistent with respect to sample size, AD diagnosis and food measures. Further, the majority of studies (81.3%) included samples with mean baseline ages that were at risk for AD based on age (>65 years), ranging from 52.0 to 85.4 years. The range of follow-up periods was 1.5-32.0 years.
CONCLUSIONS
The mean age of the samples poses a limitation in determining the influence of diet on AD; given that AD has a long prodromal phase prior to the manifestation of symptoms and decline. Further studies are necessary to determine whether diet is a risk or protective factor for AD, foster translation of research into clinical practice and elucidate dietary recommendations. Despite the methodological limitations, the finding that 50 of the 64 reviewed studies revealed an association between diet and AD incidence offers promising implications for diet as a modifiable risk factor for AD.
Topics: Alzheimer Disease; Databases, Bibliographic; Diet; Humans; Risk Factors
PubMed: 26887612
DOI: 10.3109/00207454.2016.1155572 -
The Canadian Journal of Neurological... Apr 2016Updated information on the epidemiology of dementia due to Alzheimer's disease (AD) is needed to ensure that adequate resources are available to meet current and future... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Updated information on the epidemiology of dementia due to Alzheimer's disease (AD) is needed to ensure that adequate resources are available to meet current and future healthcare needs. We conducted a systematic review and meta-analysis of the incidence and prevalence of AD.
METHODS
The MEDLINE and EMBASE databases were searched from 1985 to 2012, as well as the reference lists of selected articles. Included articles had to provide an original population-based estimate for the incidence and/or prevalence of AD. Two individuals independently performed abstract and full-text reviews, data extraction and quality assessments. Random-effects models were employed to generate pooled estimates stratified by age, sex, diagnostic criteria, location (i.e., continent) and time (i.e., when the study was done).
RESULTS
Of 16,066 abstracts screened, 707 articles were selected for full-text review. A total of 119 studies met the inclusion criteria. In community settings, the overall point prevalence of dementia due to AD among individuals 60+ was 40.2 per 1000 persons (CI95%: 29.1-55.6), and pooled annual period prevalence was 30.4 per 1000 persons (CI95%: 15.6-59.1). In community settings, the overall pooled annual incidence proportion of dementia due to AD among individuals 60+ was 34.1 per 1000 persons (CI95%: 16.4-70.9), and the incidence rate was 15.8 per 1000 person-years (CI95%: 12.9-19.4). Estimates varied significantly with age, diagnostic criteria used and location (i.e., continent).
CONCLUSIONS
The burden of AD dementia is substantial. Significant gaps in our understanding of its epidemiology were identified, even in a high-income country such as Canada. Future studies should assess the impact of using such newer clinical diagnostic criteria for AD dementia such as those of the National Institute on Aging-Alzheimer's Association and/or incorporate validated biomarkers to confirm the presence of Alzheimer pathology to produce more precise estimates of the global burden of AD.
Topics: Alzheimer Disease; Databases, Bibliographic; Dementia; Humans; Incidence; Prevalence; Residence Characteristics
PubMed: 27307128
DOI: 10.1017/cjn.2016.36 -
Journal of the American Geriatrics... Sep 2016Evidence has shown that although all individuals with dementia will eventually need to stop driving, most can continue to drive safely early in the disease. Fitness to... (Review)
Review
Evidence has shown that although all individuals with dementia will eventually need to stop driving, most can continue to drive safely early in the disease. Fitness to drive needs to be monitored, and the use of cognitive testing to determine driver safety has been suggested. This review is the first to examine cognitive test results pertaining only to individuals with dementia. The aim was to examine the relationship between cognitive tests and driving to determine whether a cognitive assessment can be implemented as a tool to examine driver safety. A systematic review of 28 studies investigating the relationship between cognitive functioning and driving in individuals with dementia was conducted. The results of this review demonstrated a lack of consistency in the findings, with some studies showing a relationship between cognitive testing and driving performance for individuals with dementia, whereas others did not. Results relating to individual cognitive tests and measures confined to a single cognitive domain were variable and not consistently associated with driving performance. Studies consistently found that composite batteries predicted driving performance. The findings from this review support the use of composite batteries comprising multiple individual tests from different cognitive domains in predicting driving performance for individuals with dementia. Scores on individual tests or tests of a single cognitive domain did not predict driver safety. The composite batteries that researchers have examined are not clinically usable because they lack the ability to discriminate sufficiently between safe and unsafe drivers. Researchers need to develop a reliable, valid composite battery that can correctly determine driver safety in individuals with dementia.
Topics: Aged; Aged, 80 and over; Alzheimer Disease; Automobile Driver Examination; Disability Evaluation; Humans; Neuropsychological Tests; Psychometrics
PubMed: 27253511
DOI: 10.1111/jgs.14180 -
Dementia and Geriatric Cognitive... 2018Cognitive therapy is a well-established intervention for treating elderly suffering from dementia. In particular, reality orientation and skills training seem to be... (Comparative Study)
Comparative Study Review
BACKGROUND
Cognitive therapy is a well-established intervention for treating elderly suffering from dementia. In particular, reality orientation and skills training seem to be effective interventions for reversing cognitive impairment among elderly, although findings are inconclusive. Therefore, a systematic update of the existing evidence of cognitive therapy for people suffering from dementia is needed.
AIM
To review existing scientific evidence regarding the efficacy of cognitive therapies for elderly suffering from dementia.
METHODS
Studies were retrieved from several bibliographic databases (January 2009 to December 2017) with prespecified selection criteria, data extraction, and methodological quality assessment.
RESULTS
In total, 10 reality orientation, 25 skills training, and 12 mixed trials were identified as meeting the inclusion criteria and were systematically reviewed. Results from reality orientation trials showed minor effects for cognitive assessments, while skills training trials and mixed trials showed contradicting effects on cognition. Effects on other outcomes (e.g., daily functioning, depression, language) were limited or not found.
CONCLUSIONS
Skills training trials and mixed trials seem to affect cognitive impairment in a positive way, although the results are inconclusive. Comparison between studies was difficult due to differences in form of intervention. Because findings are inconclusive, more structuralized and comparable randomized controlled trials are needed.
Topics: Adaptation, Psychological; Aged; Alzheimer Disease; Cognition; Cognition Disorders; Cognitive Behavioral Therapy; Depressive Disorder; Female; Humans; Language; Male; Randomized Controlled Trials as Topic; Reality Testing; Treatment Outcome
PubMed: 30092585
DOI: 10.1159/000490851 -
Nutrition Reviews May 2022Randomized controlled trials (RCTs) testing supplementation with eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids have failed to provide evidence supporting... (Meta-Analysis)
Meta-Analysis
CONTEXT
Randomized controlled trials (RCTs) testing supplementation with eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids have failed to provide evidence supporting a suggested inverse association between fish intake and dementia risk.
OBJECTIVE
Dose-response analyses were conducted to evaluate associations between fish intake, all-cause dementia or Alzheimer's Disease (AD), and the effect of EPA/DHA supplementation on cognitive performance.
DATA SOURCES
PubMed, Scopus and Web of Science databases were searched for original research evaluating either associations between fish intake and dementia or AD, or the impact of EPA and/or DHA supplementation on the risk of cognitive decline.
DATA EXTRACTION
Data were collected on study characteristics and methods; number of cases/deaths (for observational studies); categories of exposure; model covariates; risk estimates from the most-adjusted model; type and dosage of supplementation (from RCTs); fatty acid levels in blood; and differences in cognition test results before and after supplementation. Risk of bias was assessed through the ROBINS-E and RoB2.0 tools for observational and experimental studies, respectively.
DATA ANALYSIS
Weighted mixed-effects models were applied, allowing for the inclusion of studies with 2 levels of exposure. Based on findings with low/moderate risk of bias, fish intake of up to 2 portions (250 g) per week was associated with a 10% reduction (95% confidence interval [CI]: 0.79, 1.02, Ν = 5) in all-cause dementia and a 30% reduction (95% CI: 0.54, 0.89, Ν = 3) in AD risk. Changes in EPA and DHA body status had a positive impact on participants' executive functions, but not on their overall cognitive performance.
CONCLUSION
The protection offered by fish intake against cognitive decline levels off at intakes higher than 2 portions/week and likely relates to the impact of EPA and DHA on the individual's executive functions, although there remain questions about the mechanisms linking the short- and long-term effects.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO registration no. CRD42019139528.
Topics: Alzheimer Disease; Animals; Cognitive Dysfunction; Dietary Supplements; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Omega-3; Humans
PubMed: 34605891
DOI: 10.1093/nutrit/nuab078 -
Environmental Research Nov 2017Neurodegenerative processes encompass a large variety of diseases with different pathological patterns and clinical presentation such as Amyotrophic Lateral Sclerosis... (Review)
Review
Neurodegenerative processes encompass a large variety of diseases with different pathological patterns and clinical presentation such as Amyotrophic Lateral Sclerosis (ALS), Alzheimer Disease (AD) and Parkinson's disease (PD). Genetic mutations have a known causative role, but the majority of cases are likely to be probably caused by a complex gene-environment interaction. Exposure to metals has been hypothesized to increase oxidative stress in brain cells leading to cell death and neurodegeneration. Neurotoxicity of metals has been demonstrated by several in vitro and in vivo experimental studies and it is likely that each metal could be toxic through specific pathways. The possible pathogenic role of different metals has been supported by some epidemiological evidences coming from occupational and ecological studies. In order to assess the possible association between metals and neurodegenerative disorders, several case-control studies have also been carried out evaluating the metals concentration in different biological specimens such as blood/serum/plasma, cerebrospinal fluid (CSF), nail and hair, often reporting conflicting results. This review provides an overview of our current knowledge on the possible association between metals and ALS, AD and PD as main neurodegenerative disorders.
Topics: Alzheimer Disease; Amyotrophic Lateral Sclerosis; Environmental Pollutants; Humans; Metals; Parkinson Disease, Secondary
PubMed: 28777965
DOI: 10.1016/j.envres.2017.07.048 -
Neuroscience and Biobehavioral Reviews Sep 2023Several studies demonstrated that individuals are more likely to remember emotional than neutral information; this phenomenon is known as emotional enhancement of memory... (Meta-Analysis)
Meta-Analysis Review
Several studies demonstrated that individuals are more likely to remember emotional than neutral information; this phenomenon is known as emotional enhancement of memory (EEM). Adults generally tend to remember negative information more efficiently than neutral or positive items. In contrast, healthy elders seem to show an opposite bias for positive information, but results are inconsistent, also because during aging, elaboration of emotional information could change as a consequence of cognitive impairment. In this systematic review and meta-analysis, we conducted literature search of studies investigating emotion memory biases in mild cognitive impairment (MCI) and Alzheimer's disease (AD) on PubMed, Scopus and PsycINFO databases following PRISMA guidelines. The findings showed that emotional memory biases are still present despite the presence of cognitive impairment, both in MCI and at least in early stages of AD. However, the direction of emotion memory biases is not consistent across studies. These results suggest that patients with cognitive impairment might still benefit from EEM and help to define targets of intervention for cognitive rehabilitation in pathological aging.
Topics: Humans; Aged; Alzheimer Disease; Neuropsychological Tests; Cognitive Dysfunction; Mental Recall; Bias
PubMed: 37286118
DOI: 10.1016/j.neubiorev.2023.105277 -
Brain Imaging and Behavior Dec 2023The hippocampus is a complex structure that consists of several subfields with distinct and specialized functions. Although numerous studies have been performed to... (Meta-Analysis)
Meta-Analysis Review
The hippocampus is a complex structure that consists of several subfields with distinct and specialized functions. Although numerous studies have been performed to explore hippocampal atrophy at the sub-regional level in mild cognitive impairment (MCI) and Alzheimer's disease (AD), the results have been inconsistent especially for whether and which subfields can be served as the most potential biomarkers in MCI and AD. Herein, we used a meta-analytic approach to synthesize the extant literatures on hippocampal subfields in MCI and AD through PubMed, Web of Science, and Embase (PROSPERO CRD42021257586). As a result, a total of twenty studies using Freesurfer 5 and Freesurfer 6 were included in this investigation. These studies revealed that at the sub-regional level, hippocampal subfield volume reductions in MCI and AD were not restricted to specific subfields, and subiculum and presubiculum had the largest z-scores across most comparisons. However, none of the subfield performed much better in discriminating MCI and HC, AD and MCI, AD and HC as compared to whole hippocampus volume. These results suggested that we should explore the changes in the hippocampal subfields in subtypes of MCI or even at an earlier stage, that is subjective cognitive impairment.
Topics: Humans; Alzheimer Disease; Magnetic Resonance Imaging; Cognitive Dysfunction; Hippocampus; Atrophy
PubMed: 37768441
DOI: 10.1007/s11682-023-00804-3 -
Alzheimer's & Dementia : the Journal of... Dec 2023We conducted a systematic literature review and meta-analysis of empirical evidence on expected and experienced implications of sharing Alzheimer's disease (AD)... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
We conducted a systematic literature review and meta-analysis of empirical evidence on expected and experienced implications of sharing Alzheimer's disease (AD) biomarker results with individuals without dementia.
METHODS
PubMed, Embase, APA PsycInfo, and Web of Science Core Collection were searched according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results from included studies were synthesized, and quantitative data on psychosocial impact were meta-analyzed using a random-effects model.
RESULTS
We included 35 publications. Most personal stakeholders expressed interest in biomarker assessment. Learning negative biomarker results led to relief and sometimes frustration, while positive biomarkers induced anxiety but also clarity. Meta-analysis of five studies including 2012 participants (elevated amyloid = 1324 [66%], asymptomatic = 1855 [92%]) showed short-term psychological impact was not significant (random-effect estimate = 0.10, standard error = 0.23, P = 0.65). Most professional stakeholders valued biomarker testing, although attitudes and practices varied considerably.
DISCUSSION
Interest in AD biomarker testing was high and sharing their results did not cause psychological harm.
HIGHLIGHTS
Most personal stakeholders expressed interest in Alzheimer's disease biomarker assessment. Personal motivations included gaining insight, improving lifestyle, or preparing for the future. There was no short-term psychological impact of sharing biomarker status, implying it can be safe. Most professional stakeholders valued biomarker testing, believing the benefits outweigh the risk. Harmonized guidelines on biomarker testing and sharing results are required.
Topics: Humans; Alzheimer Disease; Amyloid; Biomarkers; Amyloidogenic Proteins; Amyloid beta-Peptides
PubMed: 37496313
DOI: 10.1002/alz.13410